You've probably heard the saying "everything's relative". When you consider our place in the Universe, everything really is relative. I'm recording this halfway up Vancouver Island, in the Pacific Ocean, off the West Coast ...

(Phys.org) —The nearby star Fomalhaut A hosts the most famous planetary system outside our own Solar System, containing both an exoplanet and a spectacular ring of comets. Today, an international team of astronomers announced ...

Every year, October is designated as American Archive Month. While many people may think "archive" means only dusty books and letters, there are, in fact, many other types of important archives. This includes the use of archives ...

The detection of four short bursts of radio waves, possibly arising from explosions billions of light years away, could be powerful tools to study our Universe, according to research published in Science.

A team of astronomers has discovered enormous arms of hot gas in the Coma cluster of galaxies by using NASA's Chandra X-ray Observatory and ESA's XMM-Newton. These features, which span at least half a million light years, ...

Using NASA's super-sensitive Chandra X-ray space telescope, a team of astronomers led by Q. Daniel Wang at the University of Massachusetts Amherst has solved a long-standing mystery about why most super massive black holes ...

Light-year

A light-year or light year (symbol: ly) is a unit of length, equal to just under 1013 kilometres. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in a vacuum in one Julian year.

The light-year is often used to measure distances to stars and other distances on a galactic scale, especially in non-specialist and popular science publications. The preferred unit in astrometry is the parsec, because it can be more easily derived from, and compared with, observational data. The parsec is defined as the distance at which an object will appear to move one arcsecond of parallax when the observer moves one astronomical unit perpendicular to the line of sight to the observer, and is equal to approximately 3.26 light-years.

The related unit of the light-month, roughly one-twelfth of a light-year, is also used occasionally for approximate measures.